The objective of this proposal is to define the intrinsic role of nuclear proteins in the assembly and function of the nuclear matrix during spermatogenesis in the mouse. This will include elucidating the nature of polypeptides comprising the synaptonemal complex and the role of matrix proteins as determinants of sperm nuclear shape. The study will involve a complete characterization by two-dimensional polyacrylamide gel electrophoresis of chromosomal and matrix proteins from germ cells at successive stages of differentiation. Spermatogenic cells will be isolated in homogeneous populations using sedimentation velocity at unit gravity. Nuclear matrices complete with synaptonemal complexes, isolated from pachytene spermatocytes, will be used as immunogens to prepare monoclonal antibodies by the hybridoma technique. The latter are to be used as probes to study the morphological assembly and metabolism of the synaptonemal complex during the course of meiotic prophase. Both biochemical and morphological studies will be performed to identify and define the function of constituent polypeptides.